Java GregorianCalendar hashCode()方法

java.util.GregorianCalendar.hashCode() 是Java中的一个内置函数，可以为这个GregorianCalendar实例生成哈希代码。

语法

public int hashCode()

参数： 此函数不接受任何参数。

返回值: 此函数返回一个整数值，代表此GregorianCalendar实例的哈希代码。

例子

Input : Thu Jul 24 00:53:29 UTC 1997
Output : 2121703905

Input : Tue Jul 24 00:54:11 UTC 2018
Output : -909136554

下面的程序说明了java.util.GregorianCalendar.hashCode()函数：

程序1 :

// Java Program to illustrate hashCode() function
// of GregorianCalendar class
  
import java.io.*;
import java.util.*;
  
class GFG {
     public static void main(String[] args) {
      
      // Create a new calendar
      GregorianCalendar c = (GregorianCalendar) 
                GregorianCalendar.getInstance();
  
      // Display the current date and time
      System.out.println("Current Date and Time : "
                                    + c.getTime());
        
      // Display hashcode for this calendar
      System.out.println("Hash Code:" + c.hashCode());
   }
}

输出。

Current Date and Time : Fri Jul 27 11:43:16 UTC 2018
Hash Code:-612105832

程序2

// Java Program to illustrate hashCode() function
// of GregorianCalendar class
  
import java.io.*;
import java.util.*;
  
class GFG {
     public static void main(String[] args) {
      
      // Create a new calendar
      GregorianCalendar c = (GregorianCalendar) 
                 GregorianCalendar.getInstance();
  
      // Display the current date and time
      System.out.println("Current Date and Time : "
                                     + c.getTime());
        
      c.add((GregorianCalendar.YEAR), -12);
      System.out.println("Modified Date and Time : "
                                    + c.getTime());
        
      // Display hashcode for this calendar
      System.out.println("Hash Code of the " + 
      "modified date and time:" + c.hashCode());
   }
}

输出。

Current Date and Time : Fri Jul 27 11:43:18 UTC 2018
Modified Date and Time : Thu Jul 27 11:43:18 UTC 2006
Hash Code of the modified date and time:-1346149059

**参考资料: ** https://docs.oracle.com/javase/7/docs/api/java/util/GregorianCalendar.html#hashCode()